You can create processes for users, orders and purchases. When choosing you need to consider what you want to receive eventually and by which main object (a user, an order, a purchaser) actions will be performed by.
Thus lists of actions differ depending on chosen object.
Mind, that if you have a process for orders, then mailings included to it should be for orders as well. Objects should be matched.
Usage of variables depends on objects too.
Below you will see lists of actions by every type of objects:
1. Process for users: add «Operation» block:
2. Process for orders: add «Operation» block:
3. Process for purchases: add «Operation» block: